Hot Spring Spa Insulation vs. Air Insulation
Manufacturers’ Claims can be confusing. Get the Facts.
Hot Spring, The Energy Smart Spa, is fully insulated with multiple layers of high-density polyurethane foam.
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Layers of foam are strategically applied to the spa shell and within the cabinet cavity. Foam density varies, including 30 lb, 2 lb, 5lb and 40 lb foam to provide significant energy efficiency
When considering purchasing a spa with “air space” insulation, you should know...
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When air is trapped in a small space it is unable to move, therefore it is unable to create a convection (movement) atmosphere. In this environment air can be a relatively good insulator, for example in thermal windows. However if you didn't need to see through windows foam would be a better insulator.
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In large, unobstructed areas such as air gaps in some spas, the air is free to move. This establishes a convection(movement) atmosphere in which heat is readily lost. For example, when you blow air over a hot drink it cools very quickly. When air cannot move it’s a good insulator, but when it can move it’s a poor insulator.
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Further, When the relative humidity level in the air is high (as in a spa), airs thermal properties are further reduced.
Convection + High Humidity = Low Thermal Properties of Air
To get a better understanding of Hot Spring Spa insulation vs. Air insulation, you should know...
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Material
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Tickness
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“R” Value*
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Polyurethane Foam (Hot Spring)
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1”
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6.25” inch/inch
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Air Space (includes convection)
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1”
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0.90” inch/inch
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*“R” value is a rating of insulating materials - the higher the “R” Value the better the insulation.
Polyurethane Foam is more that 6 times better than air as an insulator.